The primary objective of this project is to conduct the necessary studies required to evaluate the efficacy, potential benefit, and role of negative pi mesons (pions) in the management of all types and stages of solid tumors not well managed by current methods or combinations thereof, as follows: (1) human radiobiology studies to establish the relative biological effectiveness (RBE) of critical normal structures surrounding metastatic lesions by comparing dose response curves for pions and control x-radiation, using subtolerance doses; (2) pilot studies to establish the response of primary tumors and surrounding normal structures to increasing doses of pions; and imminently (3) Phase III studies to establish the response of primary tumors and surrounding normal structures to curative doses of pions as compared to control x-radiation. These studies are being conducted as a joint project of the University of New Mexico Cancer Research and Treatment Center and the Los Alamos Scientific Laboratory, using pions producing at the Los Alamos Meson Physics Facility. A total of 14 institutions throughout the nation will be sending patients to Los Alamos for pion therapy and entering patients in control studies in their home institutions. It has been determined that computer-assisted tomographic (CAT) scanning is essential to the application of pion radiation to deep-seated lesions. Futher, the need for the CAT scanner to be dedicated to pion therapy has become apparent because of the unique properties of the pion beam, and bacause of the accelerating admissions to the program, consistent with the projected pion patient caseload for this project. The purpose of this supplemental application is to request funds for the balance of the purchase price of the CAT scanner (supplementing funds awarded earlier) and additional patient cost funds to support CAT scanning requirements for this project until the installation of a pion-dedicated CAT scanner.